High tension electric insulator



Oct. 8,19 0- HANS-FRED! SCHWARTZ 2,217,420

HIGH TENSION ELECTRIC INSULATDR I Filed May 10, 1938 Patented Oct. 8, 1940 UNITED STATES PATENT OFFICE or to C.

Lorena Aktiengeaellschaft, Berlin- .lempelhof, Lorenswcg, Germany, a company Application May 10,1938, Serial No. 208,981

In Germany May 7, 1937 g 2 Claims. (CL 174-140) The present invention relates to high tension electric insulators, and more particularly to the type supported from below.

In order to reliably prevent flashing-over at 5 high electrical tensions, insulators of the type supported from below have in the past been provided with a bunched circumferential projection in front of the electrodes. The inner surface of m the projection has been coated with a layer of metal so as to obtain a favorable fleld distribution. v

The invention consists in certain features of novelty which will appear from the following description and be pointed out in the appended claims, reference being made to the accompanying drawing the single figure of which illustrates a longitudinal cross section through one insulator according to the invention.

a The favourable fleld distribution above referred to is still enhanced according to the invention by excavating the insulator in its longitudinal direction and covering the inner wall of the hollow thus obtained by a layer of metal. such as a silver burned thereon. Investigations have proven that the, safety against flashing-over is widely increased on account of the field distribution obtained in this manner.

Referring to the figure which represents one a embodiment according to the invention, I denotes an insulating body supported from below at'l. Thisbodyishollowasshownatl andthe inner wall of this hollow portion is coated with a layer of metal 3. The upper portion 4 of the insulator is cup-shaped and carries an annular projection or flange i so as to reach over the metallic layer 0.

What is claimed is:

l. A stand-off insulator of the type supported from below which comprises an elongated body of insulation having upper and lower ends and having a hollow extending longitudinally from said lower end into the interior thereof; a flange of insulation having the general shape of a cup, formed integral with said elon ated body. extending circumferentially around said body in- 5 termediate said ends but wholly beyond said cavity. and curving towards said upper end to define an inner surface directed towards said upper end; a conducting metallic layer applied over the upper end of said body and extending continuously over said. inner surface of said cupped flange; an internal rim of insulation extending inwardly towards said upper end of said bodyfromsaidcuppedfiangesoastopartially cover said conducting metallic layer; and a further conducting layer applied over the surface of said longitudinally extending hollow.

2. An insulator according to claim 1, wherein said further conducting metallic of alayer of silverburned ontothesurface of the body of insulation.

HANS-FRED! BOHWAR'IZ. 

